Internal gear oil pump rotor

摘要

An internal gear oil pump rotor assembly which enables the construction of an oil pump that is compact and has high performance. In the oil pump rotor assembly having an inner rotor (10) and an outer rotor (20), the number of teeth "Zi" of the inner rotor (10) with trochoid tooth profiles is set to be equal to or fewer than "6", and a ratio Si/So is set so as to satisfy the following inequalities: 0.8‰¤Si/So‰¤1.3, where Si is a cross-sectional area of one external tooth (11) which is formed outside a root circle (di) that is formed along the bottoms of the external teeth (11) of the inner rotor (10), and So is a cross-sectional area of one internal tooth (21) which is formed inside a root circle (Do) that is formed along the bottoms of the internal teeth (21) of the outer rotor (20).